PROJECT SUMMARY Heroin abuse and addiction is a major public health problem in the United States. Although there are FDA- approved heroin addiction pharmacotherapies, deaths from overdose are on the rise and current pharmacotherapies possess unwanted side effects. Immunopharmacotherapy has emerged as an alternative treatment option for heroin addiction and preclinical evaluation of a heroin vaccine immunopharmacotherapy represents a critical component in the addiction medication development process. This proposal will determine the efficacy and specificity of a heroin-TT conjugate vaccine in two behavioral procedures in nonhuman primates, while also assessing the impact the vaccine has on pharmacokinetic parameters of heroin. Aim 1 will determine the effects of the heroin-vaccine on abuse-related subjective effects in a two-key food-reinforced fentanyl vs. saline drug discrimination procedure in three males and three female rhesus monkeys. Heroin and its metabolites 6-acetylmorphine (6-AM) and morphine will be administered in a cumulative-dosing test procedure to determine their ability to produce fentanyl-like discriminative stimulus effects. Next a heroin-TT conjugate vaccine will be administered and dose-effect functions will be redetermined. Aim 2 will determine heroin-TT vaccine effects heroin and its metabolites antinociceptive properties in a warm-water tail withdrawal procedure. The same six monkeys will be trained to sit calmly in a chair, and tails will be dipped in warm water heated to 38C, 50C, and 54C and baseline latencies to withdrawal tails from water will be determined. Test sessions will be conducted after administration of fentanyl, heroin, 6-AM, and morphine. Following baseline test determinations, the heroin- TT conjugate vaccine will be administered and the dose-effect curves will be redetermined. Aim 3 will correlate heroin pharmacokinetics with heroin behavioral effects before and after heroin-TT conjugate vaccine administration. Heroin, 6-AM and morphine levels will be analyzed and quantified by high-performance liquid chromatography?tandem mass spectrometry. Overall, the proposed research will improve our understanding of the potential utility of immunopharmacotherapy for the treatment of heroin addiction.